Histamine excites rat lateral vestibular nuclear neurons through activation of post-synaptic H2 receptors.
Through whole-cell patch recordings in brainstem slices, the effects of histamine on neuronal activity of the lateral vestibular nucleus (LVN) were investigated. Bath application of histamine elicited a concentration-dependent excitation of both spontaneous firing (n=19) and silent (n=7) LVN neurons. Moreover, histamine induced a stable inward current in the LVN neurons (n=5) and the histamine-induced depolarization of membrane potential persisted in the presence of tetrodotoxin (n=4), indicating a direct post-synaptic effect of the histamine on the LVN neurons. Selective histamine H2 receptor antagonist ranitidine effectively blocked the histamine-evoked excitatory responses on the LVN neurons (n=4), but selective histamine H1 receptor antagonist triprolidine did not (n=4). In addition, selective histamine H2 receptor agonist dimaprit (n=3) rather than 2-pyridylethylamine (n=4), a selective histamine H1 receptor agonist, mimicked the excitatory action of histamine on LVN neurons. The results demonstrate that histamine excites the LVN neurons via post-synaptic histamine H2 receptors and suggest that the central histaminergic projection arising from the hypothalamus may modulate LVN neurons activity and actively influence the vestibular reflexes and functions.
Zhang
Jun
J
Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Mailbox 426, Nanjing University, 22 Hankou Road, Nanjing 210093, China.
Han
Xiao-Hu
XH
Li
Hong-Zhao
HZ
Zhu
Jing-Ning
JN
Wang
Jian-Jun
JJ
D000200:Action Potentials / Q000187:drug effects*; D006631:Amine Oxidase (Copper-Containing) / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D011899:Ranitidine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011970:Receptors, Histamine H2 / Q000502:physiology*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology; D003689:Vestibular Nucleus, Lateral / Q000166:cytology*
D006635:Histamine H2 Antagonists; D011970:Receptors, Histamine H2; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D011899:Ranitidine; D006631:Amine Oxidase (Copper-Containing)